Otto francke



O. FRANGKE.

DEVELOPING DISH. v

Patented Mar. 29, 1892.

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(No Model.)

UNITED STATES PATENT OFFICE.

OTTO FRANOKE, OF DRESDEN, GERMANY.

DEVELOPlNG-D|SH.

SPECIFICATION forming part of Letters Patent No. 471,542, dated March29, 1892. Application filed June 22, 1891 Serial No. 897,109. (Nomodel.)

To aZZ whom it may concern.-

Be it known that. I, OTTO FRANCKE, a subject of the King of Saxony, anda resident of the city of Dresden, in Saxony, Germany, have invented anew and useful closed developing-dish for photographers for developing,fixing, &c., in daylight and in the same dish, of which the following isa specification.

The vessels heretofore commonly used for receiving the developingsolution and the plate to be developed have ordinarily been shallow openreceptacles. The plate contained in such vessel has to be repeatedlylifted out for inspection. As the plate in this operation has to beprotected against daylight, such vessel can be used only in thedark-room. This is in itself very fatiguing and makes it desirable tofind a remedy therefor; but, moreover, plates exposed, say, whentraveling, where a dark-room is rarely accessible, can very seldom bedeveloped forthwith, so as to enable the operator to know whether theyare fit for use or not. This compels the operator to make severalexposures for a given object, thus materially exhausting the limitedstock of plates he carries for a proportionately smallnumber ofpictures.

The following considerations are also of importance: First, under theinfluence of the atmosphere the developing solutions deteriorate, andhence soon become useless; second, celluloid films, stripping-films, andsensitized (negative) papers are apt to curl up in the solution, or atleast to buckle, so that unequal development is apt to take place;third, on board ship the ordinary developing-dishes are absolutelyuseless, owing to the movements of the vessel; fourth, in the usualpractice of developing it is almost impossible to avoid spilling some ofthe solution, whereby clothing, fingers, and utensils become soiled. Toovercome these defects, portable photographic closed developing-disheshave been employed, made partly of tinted glass, which, while imperviousto the actinic rays of light, is nevertheless transparent, so that afilm or plate within the disk can be observed without removing the filmor plate from the dish. These dishes are adapted to receive a sensitizedfilm or plate and to thereafter receive the proper developing-liquidswithout sub= jecting the sensitized plate or film to the direct rays oflight.

The present invention consists in improvements in the construction ofthis class of developing-dishes.

The improvements constituting the present invention are illustrated inthe accompanying drawings, wherein- Figure 1 is a longitudinal sectionof the developing dish or capsule employed. Fig. 2 is a transversesection thereof. Fig. 3 is a detail View of one end thereof, showing thecover for the ends of the capsule and the means for its attachment. Fig.4: is a longitudinal section of the capsule and of a filling-bulbtherefor. Fig. 5 is a similar view to Fig. 4, showing a modification inthe filling means.

The primary feature of the improved developing-dish consists in.a flatcapsule a, open at two opposite narrow sides and made of atransparentmaterial-say glass, celluloid, or the like-covered with a red cover. Thedimensions of the capsule are such as agree with a definite size ofplate, the interior thickness being but little more than that of such aplate. The open sides of the capsule may be closed by a rubber cap I),as shown in Fig. 3, secured by a rubber ring I) placed around it, or byother means. This is the simplest form of the developing-vessel, andintended for home use the plate is inserted into the capsule a, one endwhereof is closed by the cap b, the developing solution being introducedeither before or after the plate, and, lastly, the second aperture isalso closed. This is best done in the absence of sunlight in thedark-room, if one .is at command. The progress of the development,however, can be watched in the light, as the red color of the capsuleprevents the injurious effect the light would otherwise produce upon theplate, while its transparency allows the development to be watched without removal of the plate from the capsule.

It will be evident to experts that in developing dishes of thischaracter, first, the watching of the progress of the development ismaterially facilitated and little strain is put upon the eyesight, asthe development need not take place in the distressing red light of adark room 5 second, great economy is attained in the use of developingsolutions; third, ab

. is sufficient for this purpose.

solute cleanliness is obtained, which is of special value; fourth, thecurling up of celluloid films, stripping-filn1s,paper negatives, and thelike is avoided, and thus every part of the same is equally acted uponby the developer.

Amoreperfect form of myimproved developing-vessel serves to enabledevelopment to be effected away from home-say when traveling-so that theoperator may develop his image at any desired place immediately afterexposure and without the necessity of a darkroom. To this end one of theclosing-caps b is connected with a pipe 0, which joins either with arubber bulb d, as shown in Fig. 4:, or, as shown in Fig. 5, with a tubef, rising from a bottle g. The bottle g or the bulb d, of somewhatgreater capacity than the capsule a, serves to receive the developer.The second cap I) has a short narrow tubular extension e turned outwardtherefrom. If an image is to be developed, that cap I) which isconnected with the bulb d or the bottle g, as thecase may be, is slippedover one aperture of a, and the flow of the developing solution to thecapsule a is prevented by a clamp placed on the tube a in the usualmanner. After the plate has been introduced under cover of a dark cloth,the second cap is also placed upon capsule a. No protection againstlight is required after this, as the color of the capsule The clamp. being removed from tube 0, the developer is introduced into the capsule aby pressing upon the bulb d, (in the arrangement shown in Fig. 4,) or byforcing air into the bottle g, Fig. 5. By replacing the clamp on tube 0the liquid is retained in the capsule. The tubular extension e on theother cap I) allows the escape of air from the capsule a when thedeveloping solution enters. When required, this extension is also closedby a clamp. On completion of the development the solution is returned tothe bulb d or bottle g by passing the plate into other similar apparatusfilled with water and fixing solution. The plate can be washed and fixedalso without the aid of a dark-room. a

What I claim, and desire to secure byLetters Patent of the UnitedStates, is

1. A developingdish for photographers, consisting of aflat capsule. openat its two opposite narrow sides or ends, said capsule being transparentand of a red color, in combination with inclosing caps forthe open endsof said capsule, each of said caps being of an elastic material, such asindia-rubber, so as to be drawn over the ends of the capsule, and anelastic band or ring I) for securing each of said caps in placeon saidcapsule, substantially as set forth. 7

2. A developingdish for photographers, consisting of a flat capsule openat its two narrow sides or ends, said capsule being transparent and of ared color, in combination with removable caps for the two open ends ofsaid capsule, one of said caps having av tube 0, wherebya developing orfixing solution maybe introduced into said capsule and the other of saidcaps having a tubular extension e for allowing egress and ingress ofair, substantially as set forth.

In testimony whereof I have signed this specification in thepresence oftwo subscribing witnesses.

' OTTO FRANOKE. Witnesses:

PAUL EssER, PAUL DUOKEMK.

